﻿using UnityEngine;
#if UNITY_EDITOR
using UnityEditor;
#endif
using System.Reflection;

//https://www.reddit.com/r/Unity3D/comments/1s6czv/inspectorbutton_add_a_custom_button_to_your/
//https://raw.githubusercontent.com/zaikman/UnityPublic/master/InspectorButton.cs

/// <summary>
/// This attribute can only be applied to fields because its
/// associated PropertyDrawer only operates on fields (either
/// public or tagged with the [SerializeField] attribute) in
/// the target MonoBehaviour.
/// </summary>
namespace Parallel.EditorTools
{
    [System.AttributeUsage(System.AttributeTargets.Field)]
    public class InspectorButtonAttribute : PropertyAttribute
    {
        public static float kDefaultButtonWidth = 80;

        public readonly string MethodName;

        private float _buttonWidth = kDefaultButtonWidth;
        public float ButtonWidth
        {
            get { return _buttonWidth; }
            set { _buttonWidth = value; }
        }

        public InspectorButtonAttribute(string MethodName)
        {
            this.MethodName = MethodName;
        }
    }

#if UNITY_EDITOR
    [CustomPropertyDrawer(typeof(InspectorButtonAttribute))]
    public class InspectorButtonPropertyDrawer : PropertyDrawer
    {
        private MethodInfo _eventMethodInfo = null;

        public override void OnGUI(Rect position, SerializedProperty prop, GUIContent label)
        {
            InspectorButtonAttribute inspectorButtonAttribute = (InspectorButtonAttribute)attribute;
            Rect buttonRect = new Rect(position.x + (position.width - inspectorButtonAttribute.ButtonWidth) * 0.5f, position.y, inspectorButtonAttribute.ButtonWidth, position.height);
            if (GUI.Button(buttonRect, label.text))
            {
                System.Type eventOwnerType = prop.serializedObject.targetObject.GetType();
                string eventName = inspectorButtonAttribute.MethodName;

                if (_eventMethodInfo == null)
                    _eventMethodInfo = eventOwnerType.GetMethod(eventName, BindingFlags.Instance | BindingFlags.Static | BindingFlags.Public | BindingFlags.NonPublic);

                if (_eventMethodInfo != null)
                    _eventMethodInfo.Invoke(prop.serializedObject.targetObject, null);
                else
                    Debug.LogWarning(string.Format("InspectorButton: Unable to find method {0} in {1}", eventName, eventOwnerType));
            }
        }
    }
#endif
}